Json对象直接存取数据库

需要jar包：

json.jar

jackson-core.jar

jacson-mapper.jar

 

一、ArrayList转json和hashmap转json代码一样

     /**
  * 把map转换成json对象
  * @param map 
  * @return 返回一个json
  */
 @SuppressWarnings("finally")
 public static <T> String mapToJson(T obj){
  String json=null;
  ObjectMapper mapper=null;
  try{
   mapper = new ObjectMapper();
   json=mapper.writeValueAsString(obj);//把map或者是list转换成
  }catch(Exception e){
   e.printStackTrace();
  }finally{
   mapper=null;
   return json;
  }
 }

二、json转成hashmap

      /**
  * 把json转成HashMap对象
  * @param jsonStr json值
  * @return 返回一个HashMap对象
  */
 @SuppressWarnings("finally")
 public static HashMap<String,Object> jsonToMap(String jsonStr){
  HashMap<String,Object> hashMap=null;
  ObjectMapper mapper=null;
  try{
   mapper = new ObjectMapper();
   hashMap = mapper.readValue(jsonStr, new TypeReference<Map<String,Object>>() { });//把json转成HashMap
   
  }catch(Exception e){
   e.printStackTrace();
  }finally{
   mapper=null;
   return hashMap;
  }
  
 }

public class JsonUtil {

private static ObjectMapper objectMapper = new ObjectMapper();
private static ObjectMapper objectMapperDateFormatLong = new ObjectMapper();
static {
objectMapper
.configure(
DeserializationConfig.Feature.FAIL_ON_UNKNOWN_PROPERTIES,
false);
objectMapperDateFormatLong
.configure(
DeserializationConfig.Feature.FAIL_ON_UNKNOWN_PROPERTIES,
false);
}
private static final String JSON_RESPONSE_FIELD = "jsonResponse";
private static final String STATUS_CODE_FIELD = "statusCode";
private static final String RESPONSE_FIELD = "response";
private static final String RESPONSE_INFO = "additionalInfo";

/**
* Deserialize a JSON string into a Java Object
*
* @param value
* The JSON string to be deserialized
* @param type
* The Java Object class type
* @return
* @throws IOException
*/
public static <U> U fromString(String value, Class<U> type)
throws IOException {
return objectMapper.readValue(value, type);
}

/**
* Extract the entity from a JsonResponse string. If status code is not 0,
* throw Exception
*
* @param <U>
* @param value
* The JsonResponse string to be extracted
* @param type
* The entity type to be extracted
* @return
* @throws IOException
* @throws RemoteApiCallException
*/
public static <U> U convertJsonResponseObject(String value, Class<U> type)
throws IOException, RemoteApiCallException {
JsonNode jsonResponse = null;
JsonNode rootResponse = null;
JsonNode responseInfo = null;
U responseObj = null;
try {
jsonResponse = (JsonNode) objectMapper.readTree(value).get(
JSON_RESPONSE_FIELD);
responseInfo = jsonResponse.get(RESPONSE_INFO);
rootResponse = jsonResponse.get(RESPONSE_FIELD);
responseObj = objectMapper.readValue(rootResponse.toString(), type);
} catch (IOException ex) {
if (rootResponse != null) {
throw new RemoteApiCallException(responseInfo.getValueAsText(),
jsonResponse.get(STATUS_CODE_FIELD).getIntValue(),
responseInfo.toString());
} else if (jsonResponse != null) {
throw new RemoteApiCallException(jsonResponse.get(
RESPONSE_FIELD).getValueAsText(), jsonResponse.get(
STATUS_CODE_FIELD).getIntValue(), jsonResponse);
} else {
throw ex;
}
}
if (jsonResponse.get(STATUS_CODE_FIELD).getIntValue() != 0) {
throw new RemoteApiCallException(responseInfo.getValueAsText(),
jsonResponse.get(STATUS_CODE_FIELD).getIntValue(),
responseObj);
}
return responseObj;
}

/**
* Extract the entity list from a JsonResponse string. If status code is not
* 0, throw Exception
*
* @param <U>
* @param value
* The JsonResponse string to be extracted
* @param type
* The entity type to be extracted
* @return The entity list
* @throws IOException
* @throws RemoteApiCallException
*/
public static <U> List<U> convertJsonResponseObjectCollection(String value,
Class<U> type) throws IOException, RemoteApiCallException {
JsonNode jsonResponse = null;
JsonNode rootResponse = null;
JsonNode responseInfo = null;
List<U> responseCollection = new ArrayList<U>();
try {
jsonResponse = (JsonNode) objectMapper.readTree(value).get(
JSON_RESPONSE_FIELD);
responseInfo = jsonResponse.get(RESPONSE_INFO);
rootResponse = jsonResponse.get(RESPONSE_FIELD);
Iterator<JsonNode> iterator = rootResponse.getElements();
while (iterator.hasNext()) {
String content = iterator.next().toString();
responseCollection.add(objectMapper.readValue(content, type));
}
} catch (IOException ex) {
ex.printStackTrace();

if (jsonResponse != null) {
if (responseInfo != null) {
throw new RemoteApiCallException(responseInfo
.getValueAsText(), jsonResponse.get(
STATUS_CODE_FIELD).getIntValue(), jsonResponse);

} else {
throw new RemoteApiCallException(jsonResponse.get(
RESPONSE_FIELD).getValueAsText(), jsonResponse.get(
STATUS_CODE_FIELD).getIntValue(), jsonResponse);
}
} else {
throw ex;
}
}
if (jsonResponse.get(STATUS_CODE_FIELD).getIntValue() != 0) {
throw new RemoteApiCallException(responseInfo.getValueAsText(),
jsonResponse.get(STATUS_CODE_FIELD).getIntValue(),
responseCollection);
}
return responseCollection;
}

/**
* Serialize an entity into JSON string
*
* @param value
* @return
* @throws IOException
*/
public static String toString(Object value) throws IOException {

DateFormat dateFormat = new SimpleDateFormat(
ICodeConstants.DATETIME_FORMAT);

dateFormat.setTimeZone(TimeZone.getTimeZone("PST"));

objectMapper.getSerializationConfig().setDateFormat(dateFormat);

return objectMapper.writeValueAsString(value);
}

public static String toString(Object value, boolean isDateFormat)
throws IOException {
if (isDateFormat) {
return toString(value);
} else {
return objectMapperDateFormatLong.writeValueAsString(value);
}
}

public static Integer getJsonResponseStatusCode(String value) {

JsonNode jsonResponse = null;
Integer result = -1;
try {
jsonResponse = (JsonNode) objectMapper.readTree(value).get(
JSON_RESPONSE_FIELD);
} catch (JsonProcessingException e) {

e.printStackTrace();
} catch (IOException e) {

e.printStackTrace();
}

if (jsonResponse != null) {
result = jsonResponse.get(STATUS_CODE_FIELD).getIntValue();
}

return result;

}

}